List of clinical trial registries in the world

List of clinical trial registries:

Clinical trial registries list provided here with the website urls.

Clinical trial registry is an official website that allows us to registering the clinical trials. Any body can register the clinical trails in the registry who will sponsor the study or by any organisation who is conducting the study. Usually Pharmaceutical or medical or biotech companies or research institutes will register the trials in the clinical trial registries.

Two types of registries available. They are primary registry and partner registry.

Primary registry:

Primary registries are developed according to the specific criteria given by World Health Organisation (WHO) International Clinical trial registry platform (ICTRP) This specific criteria include these 6 categories. That is Content, quality &validity, Accessibility, Unambiguous Identification, Technical capacity, Administration &governance.  Primary registry meets the requirements of International committee of medical journal editors (ICMJE). Registration of trial in the clinical trial primary registry in the WHO network or USA Clinical trial registry ( is mandatory for publishing the study in international biomedical journals. ICMJE announced this statement 15 years back and applicable from July 1st 2005 onwards. All these primary registries are linked to the WHO- ICTRP. ICTRP can directly receive the data from these primary registries.

clinical trial registries

Related: Clinical trials overview

A total number of 16 registries recognized as primary registries in the WHO registry network. Along with these 16 registries Clinical (USA) recognized by ICMJE. Along with USA registry, these 16 primary registries act as data providers to WHO. This data available in the WHO ICTRP search portal. WHO ICTRP search portal is technically not considered as a clinical trial registry. 

For eg: If you register a clinical trial in any of these 17 clinical trial registries, you can find that trial in WHO ICTRP search portal. Registries registered trail data upload to ICTRP search portal periodically.

Australia, China, UN, EU, Netherlands, USA registries uploaded Friday of the every week. Remaining registries data uploaded monthly basis.Types of clinical trial registries

List of clinical trial registries recognized by WHO network and ICMJE are follows.

List of clinical trial registries (Primary)

1. Australian New Zealand CTR (ANZ Clinical Trial Registry) –

2. Brazilian CTR (ReBec) –

3. Chinese CTR (ChiCTR) – 

4. Republic of korea Clinical Research Information Service (CRiS), –

5. CTR – India (CTRI) –

6. Cuban Public Registry of Clinical Trials (RPCEC) –

7. European Union CTR (EU-CTR) –

8. German CTR (DRKS)  –

9. Iranian Registry of Clinical Trials (IRCT) –

10. United Kingdom for International Standard Registered Clinical/soCial sTudy Number (ISRCTN) –

11. Japan Primary Registries Network (JPRN) –  (It has four networks JapicCTIJMACCT CTRjRCTUMIN CTR )

12. Thai CTR (TCTR) –

13. The Netherlands National Trial Register (NTR) –

14. Pan African CTR (PACTR) –

15. Peruvian CTR (REPEC) –

16. Sri Lanka CTR (SLCTR) –

 USA – (Recognised by ICMJE, It is not in the list of WHO registry network but act as data provider to WHO ICTRP)

WHO ICTRP- (Technically not called as a clinical trial register)

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Partner registry:  

Partner registries does not meet the requirements of ICMJE. But partner registry meets the WHO ICTRP specific criteria as mentioned above. They are affiliated to ICMJE registered primary registry or Primary registry in WHO network. It is the responsibility of primary registry to make sure that the partner registry meets the WHO registry criteria. ICTRP directly will not have access to receive the data from these partner registries. Along with 16 primary registries two partner registers available. These two registries are affiliated to Chinese clinical trial registry (ChiCTR). Partner registries can also be called as secondary registries. They are as follows.

  1. Centre for Clinical Trials, CTR – Chinese University of Hong Kong –
  2. The Acupuncture-Moxibustion Clinical Trial Registry (AMCTR) Beijing
  3. Apart from these registries, other available registries are as follows.
List of clinical trail registries (Regional)
  1. Canadian cancer trials – ( Canadian based cancer registry –Only for cancer clinical trails in Canada)
  2. Health Canada Clinical Trial Database – (It is technically not called as a registry)
  3. Hong Kong University clinical trials registry (HKUCTR)-
  4. Indonesia clinical trial registry-
  5. NBScience Clinical trial registry  (NBSCTR)- Ukraine –
  6. Philippine Health Research Registry (PHRR) –
  7. Swiss National Clinical Trials Portal (SNCTP) – -clinical-trials-portal.html
  8. South African National Clinical Trial Register (SANCTR) –
  9. Spanish registry of Clinical trials (REec) –
  10. Tanzania Clinical Trial Registry (TzCTR) –  

Feel free to comment your opinion below.

Phase 2a vs Phase 2b trials: Differences and comparison

Phase 2a vs Phase 2b trials:

Comparison of phase 2a vs phase 2b trials explained here. Phase 2 trials also known as therapeutic exploratory trials conducted in 100 to 300 patients approximately. As you already know, It explores the drug/device efficacy and evaluates the further safety. From this phase, Investigational drug testing will be done on target disease patients with the support of safety data from phase 1 clinical trials.

Related: Phases of clinical trials – Overview

Phase 2 trials conducted in well designed patient population with target disease. Sometimes phase 2 trials divided into to phase 2A and phase 2B trials. Even though both phases conducted to test the drug efficacy with further safety, types of studies conducted are different for each phase. That is Phase 2A trials known as early phase 2 trials, conducted with pharmaco-dynamics and clinical efficacy as primary end point.  These are the non-pivotal pilot studies to know the drug mechanism of action and how the drug affecting the body to show the efficacy. Phase 2B trails known as late phase 2 trials conducted to test the drug efficacy.

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Phase 2a trials:

Phase 2a trails are critical and most important trials in clinical development of a new drug. Because important decisions taken here for proceeding the further drug development. Proof of concept (PoC) studies done here. No efficacy data is not available in humans till this trails. Most of the drugs, efficacy wise perform well in animals and in non-clinical models but fail to show efficacy in the humans. So Phase 2a trials are critical. Usually Proof of concept studies conducted with two treatment groups, one group with test drug other group with placebo. First of all new drug is tested with a dose of Maximal tolerated dose (MTD) or a dose a bit lower than the MTD. The selected dose in this phase is as high as possible up to MTD, because to know the best possible efficacy. If the drug showing promising efficacy in humans with target disease, based on this proven concept, further trials will be conducted. If no promising effect observed in this trial, sponsor may stop the investments and man force for this drug tested drug. Further trials will be stopped. (Phase 2a vs Phase 2b trials continuation…)

Phase 2a vs phase 2b

Phase 2a vs Phase 2b clinical trials

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Phase 2b trials:

Based on proven efficacy from the early phase 2 trials, phase 2b trials conducted. Dose ranging studies starts here. Now they know the efficacy of a new drug at high dose but they do not the efficacy of other doses that are lower than the actual effect produced dose. So dose response studies conducted in this phase. Now the question is, which doses should be selected as test doses other than actual effect produced dose (MTD).

Different methods used to select the test doses like equal dose phasing or log dose spacing or using Fibonacci series or by other suggested approaches etc. For example effect produced high dose in phase 2a trial is 900mg. By using equal dose spacing method, calculated medium and low dose will be 600 mg and 300 mg respectively. If we use log dose spacing for high dose 900 mg we will get medium and low dose as 600 mg and 100 mg respectively. In groups new drug doses tested with placebo group. Along with these methods some other approaches are also used.

Simply we can say that phase 2a trials mainly all about proof of concept studies with Maximal tolerated dose (MTD) or a little bit lower dose. Phase 2b all about dose ranging or dose response studies with selected doses as explained above.  

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